Jointer sharpener



Jan. 10, 1956 w. H. DURST 2,729,923

JOINTER SHARPENER Filed May 1, 1953 3 Sheets-Sheet l INVENTOR. IValI/erEDllrsf ATTORNEYS Jan. 10, 1956 w. H. DURST JOINTER SHARPENER 3 Sheets-Sheet 2 Filed May 1, 1953 ATTU RN EYE INVENTOR. WiferHDmf Mj5ma Jan. 10, 1956 w. H. DURST JOINTER SHARPENER 3 Sheets-Sheet 3 Filed May 1, 1953 1N VEN TOR. Walferflfila'si ATTORNEYS United States Patent J OINTER SHARPENER Walter H. Durst, Seattle, Wash.

Application May 1, 1953, Serial No. 352,353

2 Claims. (Cl. 51-173) This invention relates to grinding and sharpening devices particularly adapted for sharpening cutter knives or blades of jointer cutter heads, and in particular an attachment adapted to be positioned on the bed in which a motor driven grinding wheel is mounted to travel transversely across the bed of the jointer for, selectively, grinding the cutter knives with the knives in position in the jointer.

The purpose of this invention is to provide a sharpen ing attachment with which all of the cutter knives of a cutter head may be ground to the same angle and to the same distance from the center while in position in the machine.

Although machines have been provided for sharpening cutter blades of large jointers the conventional method of grinding cutter knives or blades of small jointers and the like is to remove the cutter heads from the machine and the blades are removed from the cutter head, and in reassembling the cutter heads it is difficult to accurately position the cutters whereby a smooth easy cut is obtained. With this thought in mind this invention contemplates an attachment adapted to be clamped on the bed of a jointer having a cutter head therein in which a grinding wheel carried by the attachment is adapted to be moved across the cutting edges of the cutters with the wheel rotating so that one cutter after another may readily be sharpened.

The object of this invention is, therefore, to provide means for mounting a grinding wheel on the bed of a jointer whereby the grinding wheel may be moved longitudinally of the cutter blades as it is rotated and wherein the grinding wheel remains in operative position until all of the blades of the cutter head are sharpened.

Another object of the invention is to provide a grinding attachment for sharpening cutter blades of cutter heads with the blades in position in which the attachment may be mounted upon the bed of a jointer without changing and also without making permanent connections to the bed.

A further object of the invention is to provide an attachment for grinding cutter blades of cutter heads, particularly of jointers with the heads in position in which the attachment is ofa comparatively simple and economical construction.

With these and other objects and advantages in view the invention embodies a base plate adapted tobe clamped to the bed of a jointer, a gauge block pivotally mounted on the base plate and positioned to engage cutter knives of a cutter head mounted in the bed of a jointer, a carrier plate hinged to the base plate and positioned in spaced relation to the base plate, a pair of rails mounted on the carrier plate and positionedto extend transversely across the bed of the jointer, adjusting and thumb screws for clamping the parts in operative positions, and a grinding wheel carried by a motor mounted to travel in the rails of the carrier plate whereby the grinding wheel is positioned to engage sharp edgesof cutter knives of a cutter head in the jointer.

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Other features and advantages of the invention will appear from the following description taken in connection with the drawings, wherein:

Figure 1 is a side elevational view showing a jointer with the cutter knife grinding attachment positioned thereon and showing a longitudinal section through the attachment.

Figure 2 is a plan view of a jointer also showing the cutter knife grinding attachment thereon.

Figure 3 is a cross section taken on line 3--3 of Fig. 2 with the parts shown on an enlarged scale illustrating the method of clamping the attachment on the bed of the machine.

Figure 4 is a view showing a longitudinal section through part of the grinding attachment also with the parts shown on an enlarged scale and with portions of the parts broken away.

Figure 5 is a detail showing a section taken on line 5-5 of Fig. 2 illustrating the mounting: of locating pins in the attachment and showing the mounting of the cutter head in the machine.

Figure 6 is a detail showing a section taken on line 6-6 of Fig. 2 showing the driving pulley of the cutter head and illustrating a clamp for securing the cutter head in position.

Figure 7 is a detail showing a section taken on line 7-7 of Fig. 4 illustrating the mounting of the indexes block on the base plate of the attachment.

Figure 8 is a plan view also showing the indexes block mounting and illustrating the position of the gauge block on a cutter knife with part of the cutter head broken away. t

Figure 9 is a detail showing the eccentric mounting of the indexes block arm showing the pin of the eccentric mounting in the forward position.

Figure 10 is a detail similar to that shown in Fig. 9 showing the position of the eccentric pin reversed.

Referring now to the drawings wherein like reference characters denote corresponding parts the improved jointer knife grinding attachment of this invention includes a base plate 10, an indexer block 11 pivotally mounted on the base plate, a carrier plate 12 pivotally connected to the base plate with a hinge 13, a grinding wheel 14 carried by a motor 15 mounted on a slider 16 that is positioned to travel in parallel rails and a feed mechanism stop block 17.

The base plate 10 is clamped securely to the rear or outfeed end of the jointer by clamping members 18 and 19 whereby the machine is anchored securely to the jointer in which the blades are to be sharpened.

The carrier plate 12 is positioned substantially parallel to the base plate 10 and the front end of the plate, which is carried by the block 17 rests upon the front or infeed end of the jointer bed. e

The base plate is positioned on the .rear jointer bed with the front edge spaced inwardly from the front edge of the jointer bed in which position it is secured with the clamp elements. With the base plate in position the lower front jointer infeed bed is lowered by the conventional crank 26 of the machine to the desired elevation, such as one-eighth inch on steps of cut gauge.

With the carrier plate swung back about the hinge 13 the cutter head clamping mechanism is adjusted whereby a clamp block 21 is centered over a driving pulley 22 on a shaft 23 and with the block centered over the pulley a thumb screw 24 of a set collar 25 on a shaft 26 is tightened to secure a rod 27 on which the block 21 is positioned in place. I

The clamp block 21 is clamped in position with a knurled nut 28 that is threaded on a stud 29, extended from the block, and the nut 28 clamps a plate 30 against the outer flange of the pulley 22. The clamp block 21 through the upper part of the block, and as shown in Fig. 6, the screw 31 is fitted into a slot 32 in the upper edge of the plate 30. The adjusting screw 31 is also provided with a knurled head 33 and a lock nut 34. The shaft 26 is secured in bearings 35 and 36 on the base plate 10, the bearings being secured to the plate with screws 37 and 38, respectively, and the shaft being secured in the bearings 35 with a thumb screw 39.

Before tightening the screws of the clamp block 2], rotate the cutter head 40 of the jointer until the bevel on one of the knives 41 is in the same plane as that of the infeed jointer bed with the bed set at a depth of Ms inch bv the bell crank 20 using a short straight edge across the infeed jointer bed and cutter knife, then tighten the screws of the clamp block 21 thereby securing the cutter knife in the correct position for sharpening. I

With the parts in these positions swing the cutter head indexer block assembly from the position shown in Fig. 4 to that shown in Fig. 1 whereby the block is' at a right angle to the cutter knife.

The block 11 is adjustably mounted on a rod 42, being held in position with a thumb screw 43 and a base 44 of the rod 42 is pivotally mounted on a hub 45, from the sides of which eccentrically positioned pins 46 and 47.extend. "The pins 46 and 47 are pivotally mounted in plates 48 and 49, respectively, which extend upwardly from the base 50 and'the base 50 is secured to the base plate 10 with a screw 51...

The lower surface of the indexer block 11 is provided with a notch 52, the horizontally disposed surface of which is parallel to the beveled surface of the blade 41 with the parts in the position shown in Fig. 1.

Theeccentrically positioned pin 47 is provided with an extended end and a gauge lever 53 is mounted on the end, as illustrated in Figs. 9 and 10, and this lever which .is'provided with a handle 54 is positioned to engage a stop pin 55 with the block 11 positioned over a cutting blade of the cutter head. This indexer block assembly pivots on the base 50 and screw 51, so that it can swing around over the base plate where it is out of the way during the sharpening operation.

, In setting the block 11 the position of the block on the rod 42 is adjusted until the notch 52 fits exactly over the front edge of the cutter head knife with the gauge lever 53 in engagement with the stop pin 55. With the block 11 in this position the thumb screw 43 is tightened to secure the parts accurately in position.

This indexer assembly makes it possible to bring the next cutter knife into the correct position for sharpening; After setting the block 11 the gauge lever 53 is turned over to the position shown in Fig. 10 whereby the block 11 is moved forward so that the notch 52 is released from the cutter knife, cutting edge. This assembly may then be moved back to the position shown in Fig. 4 and the gauge lever 53 returned to the position shown in' Fig. 9.

With the parts in this position the carrier plate 12 is moved to the forward position shown in Fig. 1

whereby the feed mechanism stop block 17 rests upon the front or infeed bed of the jointer. In this opera t io n care should be taken to be sure that the grinding wheel 14is elevated to such a position that it clears the cutter knife 41. Also in this operation care should be taken that the feed pins 56 are positioned upwardly in the block 17 whereby they do not engage the jointer bed. The positions of the pins 56 are adjusted by turning the adjusting screw 57 with a knob 58, the lower end of the knob engaging the end of a lever 59 on a shaft 60 which also carries fingers 61 that'engage heads 62 of the pins 56. The pins 56 are resiliently urged upwardly by springs 63 and the screw 57 is threaded in a block 64 extended from the rearsurface of the block .With the parts in this position the feed crank 20 is turned to the depth whereby the jointer bed is lowered until the base plate 10 and carrier plate 12 are parallel, in which position both plates are parallel with the bed plate of the jointer. In this position the jointer infeed bed is one-quarter of an inch lower than the jointer outfeed bed, whereby the depth of the cut gauge on the jointer will read one-quarter of an inch.

With the parts in these positions the chuck 65 on the motor shaft is loosened and the grinder wheel adjusted until it comes lightly in contact with the cutter knife 41. The grinder wheel should be accurately positioned by moving the motor back and forth without the motor running to be sure that the grinding wheel is not too close to the cutter knife and after running the grinding wheel back and forth over the blade or knife the motor chuck is tightened.

The motor is adjustably mounted on a bracket 66 on the slider 16 and the slider is mounted to travel in parallel rails 67 and 68 which are mounted on the 'carrier plate 12. By. this means the motor is free to slide transversely of the jointer bed with the grinding wheel 14 extending through a transversely positioned opening 69 in a section 70 at the end of the plate 12.

The block 17 extends from the under surface of the section 70 ofthe plate 12 and the rocker shaft 60 is journaled in bearings 71 and 72 extended upwardly from the upper surface of the plate.

The plate 12 is secured to the upper plate 73 of the hinge 13 withbolts 74 and the lower plate 75 of the hinge is secured to a spacing block 76 that is positioned on the base plate 10, the block 76 being secured to the hinge and base plate, preferably by welding.

The clamp elements for securing the base plate 10 to the rear or outfeed end of the jointer bed includes thelugs 19 which are preferably welded to the base plate and which are provided with extensions 77 that grip the edge of the bed of the jointer and these extensions are held against the edge of the bed by the clamp blocks 18 which are slidably mounted on shafts 78 which extend through a bearing 79 and into the bearing 36, and the block 13 is secured against the bed of the machine with a nut 80 threaded on the end of the shaft 78. The clamp block 18 is provided with slots 81 that are positioned to'receive pins 82 for locating the clamp blocks in relation to the bed of the jointer. The bearing 79 is provided with a thumb screw 83 for securing the shaft 78 in position and the bearing is secured to the base plate with screws 84. i

The device is provided with a latch 85 which is pivotally mounted by a pin 86 in a bearing 87 on the upper surface of the base plate and, as shown in Fig. 1, this latch is positioned to extend through an opening 88 in the carrier plate 12 with a projection 89 on the end extended over the edge of the plate for retaining the plate in the position shown in Fig. 1 for transportation. When not in use the latch 85 is turned to a position upon the base plate 10, parallel to the plate.

Operation With the parts positioned as hereinbefore described an operator, gripping the motor with his left hand slides the motor back and forth and after determining that thegrinding wheel is lightly touching the cutter blade or knife the motor is started and as grinding proceeds the motor is moved back and forth' with the left hand and, with the right hand, the operator turns the ball crank 26 on the jointer thereby slowly lowering the infeed bed of the jointer until'the cutter knife is sharpened. This should not require much grinding and the crank 20 should. be turned very slowly to permit the grinding Wheel to have'ample time to doa thorough grinding job, p

After grinding the motor should be turned offend the carrier plate lifted to facilitate inspecting the -knife and should further grinding be requiredball crank located is rotated to adjust the position of the cutter head whereby the grinding operation may be repeated. This operation may be repeated several times if found necessary and after the first blade is finished the ball crank 20 should not be turned in the grinding operation of additional blades. By this means all blades may be ground so that the cutting edge of each blade is exactly the same distance from the center.

In changing from one blade to another the clamp block 21 is loosened from the pulley 22 and each blade is set with the notch 52 of the block 11 being positioned over the cutting edge of the blade.

In setting the machine for grinding the second cutter knife the carrier plate 12 is held in a vertical position and the knob 58 is turned whereby the pins 56 extend from the block 17 about one-quarter of an inch or to such positions that when the ends of the pins rest upon the jointer infeed bed the grinding wheels 14 clears the cutter knife.

In sharpening the second cutter knife instead of turning the ball crank 20 the position of the grinding wheel is adjusted by turning the knob 58 whereby the feed mechanism pins 56 recede up into the block 17 allowing the block to come to rest upon the jointer bed, whereby the grinding of the second cutter knife finishes the knife to the same distance from the center as that of the first knife.

This operation is repeated for following knives.

It will be understood that modifications, Within the scope of the appended claims, may be made in the de sign and arrangement of the parts without departing from the spirit of the invention.

What is claimed is:

1. In a cutter knife sharpening attachment for use on a jointer having a bed, a base plate, a clamp for securing the base plate to the bed of the jointer, a carrier plate hinged to and positioned above the base plate in parallel longitudinal alignment with said baseplate, a feed mechanism block carried by an extended end of the carrier plate, adjusting means in said feed mechanism block for adjusting the elevation of the carrier plate in relation to the bed of the machine, parallel rails mounted on said carrier plate and extended transversely across the base plate, a motor mounted to slide in said rails and a grinding wheel carried by the motor and positioned to engage the cutter knives of said jointer.

2. In a cutter knife sharpening attachment for a jointer having a bed, a base plate, means for clamping the base plate in position on the bed of the jointer, a carrier plate hinged to and positioned above the base plate in parallel longitudinal alignment with said base plate, a feed mechanism block carried by an extended end of the carrier plate and positioned to space the carrier plate from the bed of the jointer, resiliently held pins extended through said feed mechanism block, arms carried by a rocker shaft pivotally mounted on the carrier plate and positioned to engage the pins in the feed mechanism block, an adjusting screw for actuating the rocker shaft to adjust the pins of the feed mechanism block, an indexer block adjustably mounted on the base plate, a motor slidably mounted on the carrier plate and positioned to travel transversely across the base plate, and a grinding wheel carried by the motor and positioned to engage cutter knives of the jointer.

References Cited in the file of this patent UNITED STATES PATENTS 831,541 Davis Sept. 25, 1906 900,284 Kahle Oct. 6, 1908 1,038,500 Foley Sept. 10, 1912 1,085,876 Redden Feb. 3, 1914 2,347,800 Sjostrand May 2, 1944 2,549,147 Walters Apr. 17, 1951 2,620,606 Dvorak Dec. 9, 1952 FOREIGN PATENTS 804,070 Germany Apr. 16, 1951 

